The active compounds of this invention are heterocyclic compounds which may be represented by the following formula: ##STR1## wherein R.sub.1 is a member selected from the group consisting of C.sub.1 -C.sub.10 alkyl straight chain or branched, C.sub.2 -C.sub.7 alkenyl straight chain or branched, C.sub.3 -C.sub.8 alkynyl straight chain or branched, C.sub.3 -C.sub.7 cycloalkyl. R.sub.2 and R.sub.3 can be either hydrogen or methyl.
Substituted octahydrophenanthridines, and analogues thereof have been described and claimed by H. Chafetz et al. in U.S. Pat. Nos. 3,311,631; 3,336,313; 3,349,092; and 3,408,351 as corrosion inhibitors in oil and gas wells and also with pickling acids. The cited patents, however, do not suggest any pesticidal activity nor could the acaricidal and siphonaptericidal activity exhibited by the substituted octahydrophenanthridines claimed in the present application be anticipated therefrom.
A large number of references can be found in the published literature relating to substituted phenanthridines and their use as trypanocidal and antibacterial agents, e.g., (Chem. Abst. 41: 2449 g; 41: 2465 g; 49: 429 i); as anti-virals, (Chem. Abst. 47: 8829 b); as antidepressants, (Chem. Abst. 40: 871-882; 71: 49979 f) and as antispasmodics, (Chem. Abst. 46: 2548 a). Some of these references mention di-, tetra-, and hexahydro- analogues as having some of the above-mentioned biological and pharmacological activities, but neither of the references suggests nor anticipates ectoparaciticidal activity.